1. What is virtual water? Water embedded in commodities
It is an essential factor in calculating the real water use of a country, or its water footprint
sources

2. How Important Is It?
After Sowby, R (2015). America’s water footprint: 2,000 gallons per person, every day. Wasatch Water Review.

3. Virtual Water Trade Global virtual water trade
67% crops
33% livestock products
10% industrial products
The regions with a significant net virtual water import are: - Central and South Asia - Western Europe, North Africa - Middle East
sources

4. Top 5 virtual importing countries (1995-1999)
COUNTRY
NET IMPORT VOLUME (109 m3)
Sri Lanka
428.5
Japan
297.4
Netherlands
147.7
Korea Rep.
112.6
China
101.9
Chapagain and Hoekstra, Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products, in Hoekstra, AY ed., Virtual water trade: Proceedings of the International Expert Meeting on Virtual Water Trade. Water Footprint Org.
What is meant by “net” volume?

5. Gross Virtual Water Import and Export by Region
Chapagain and Hoekstra, Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products, in Hoekstra, AY ed., Virtual water trade: Proceedings of the International Expert Meeting on Virtual Water Trade. Water Footprint Org.
For the period of

6. Virtual Water Imports - Exports
Which regions are more dependent on other regions?
Chapagain and Hoekstra, Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products, in Hoekstra, AY ed., Virtual water trade: Proceedings of the International Expert Meeting on Virtual Water Trade. Water Footprint Org.

7. Top 3 virtual exporting countries (1995-1999)
COUNTRY
NET EXPORT VOLUME (109 m3)
USA
758.3
Canada
272.5
Thailand
233.3
Chapagain and Hoekstra, Virtual water trade: A quantification of virtual water flows between nations in relation to international trade of livestock and livestock products, in Hoekstra, AY ed., Virtual water trade: Proceedings of the International Expert Meeting on Virtual Water Trade. Water Footprint Org.
What are the ramifications of being an exporter of virtual water?

8. From Whom to Where?
Mahtani, R (2012). Assignment 2 and 3: Virtual Water Flows, in ARCH 3230: Systems, Sites and Buildings.

9. Global virtual water trade between nations: top 10 crop products (1995-1999)
% OF THE VIRTUAL WATER TRADE
wheat
30.20
soybean
17.07
rice
15.36
maize
8.85
raw sugar
7.20
barley
4.88
sunflower
2.71
sorghum
2.01
bananas
1.97
Source: A.Y. Hoekstra; P.Q. Hung. Virtual water trade - A quantification of virtual water flows between nations in relation to international crop trade.

10. Water requirement equivalent of main food products
UNIT
WATER
(m3 per unit)
cattle
head
4,000
sheep and goats
500
fresh beef kg 15
fresh poultry 6
cereals
1.5
citrus fruits 1
palm oil 2
roots and rubber
Source: FAO, Published in the UN World Water Development Report.

11. Hoekstra and Chapagain, 2007

12. Put these Values in Context
It takes ~2,500 liters to fill an Olympic-sized swimming pool.
How can it take so much water to produce these items? Where do you think it goes?

13. Water Use vs. Virtual Water Flow
Farmer
Food Processer
Retailer
Waste Water
Consumer
15,340 liters CROP WATER
Data from Hoekstra, AY (2012). The Hidden Water Resource Use Behind Meat and Dairy. Animal Frontiers, 2(2): 3-8.
1300 kg GRAIN kg ROUGHAGES + 24,000 l DRINKING + 7,000 l SERVICING
1 COW 200 kg BEEF liters in one burger

14. Put these Values in Context
Virtual Water Calculation Exercise
Estimate the number of cotton t-shirts you own.
Multiply by the virtual water content (2000 l/shirt)
How many liters of virtual water?
Estimate the number of leather shoes you own.
Multiply by the virtual water content (8000 l/pair)
How many liters water?
Add the virtual H20 content from both items together.
Divide by 2,500 liters/Olympic-sized swimming pool.
How many Olympic-sized swimming pools does this equal?

15. Put these Values in Context
What is the minimum quantity of water needed for a person per day?
The World Health Organization says “about 20 liters per capita per day should be assured to take care of basic hygiene needs and basic food hygiene,” as well as for drinking.
How many people could the virtual water of your shirts and shoes support for one day?

16. Amount of Virtual Water per Food per Country in m3/ton
U.S.
China
India
Russia
Australia
Brazil
Italy
World Avg
Rice
1903
1972
4254
3584
1525
4600
2506
3419
Wheat
849
690
1654
2375
1588
1616
2421
1334
Corn
489
801
1937
1397
744
1180
530
909
Beef
13193
12560
16482
21028
17112
16961
21167
15497
Chicken
2389
3652
7736
5763
2914
3913
2198
3918
“The big difference between the countries is due to the climate, applied technology and the amount of production related to it.”
Why the big difference in how much water it takes to produce the same food items in different countries?

17. Amount of Virtual Water per Food per Country in m3/ton
U.S.
China
India
Russia
Australia
Brazil
Italy
World Avg
Rice
1903
1972
4254
3584
1525
4600
2506
3419
Wheat
849
690
1654
2375
1588
1616
2421
1334
Corn
489
801
1937
1397
744
1180
530
909
Beef
13193
12560
16482
21028
17112
16961
21167
15497
Chicken
2389
3652
7736
5763
2914
3913
2198
3918
“The big difference between the countries is due to the climate, applied technology and the amount of production related to it.”
“The big difference between the countries is due to the climate, applied technology, and the amount of production related to it.”

18. Virtual Water Needed to Maintain a Daily Diet (L/Day)
After Schrier, H (2004). Virtual Water Calculation, in Virtual Water and Global Food Security: Implications for Canada. Univ. of British Columbia.

19. Water Requirements of Meat
The American diet requires twice as much water as diets common in some Asian and European nations.
~40% of world’s grain production went to livestock at the turn of the century.
Over the past few decades, consumption of meat in developing countries has grown at a rate of about 5 to 6% per year; consumption of milk and dairy products at 3 to 4%.
What are the ramifications of these statistics? How is this a water sustainability concern?
Sources!

20. Virtual Water Case Study Water Stress in China
There is a geographical mismatch between freshwater demand and available freshwater.
The North China Plain shows the greatest water scarcity, with per capita water availability < 150 m3/y
China has been developing:
>20 major physical water transfer projects, with a
total length >7,200 km, including the world’s largest
the South–North Water Transfer Project (SNWTP)
Zhaoa, X, Liua,J , Liua, O, Tillotsonb, M, Guanc, D, and Hubacekd, K (2014). Physical and virtual water transfers for regional water stress alleviation in China. Proceedings of the National Academy of Sciences of the USA, V. 112(4).

21. Virtual Water Case Study Water Stress in China
From Zhao, X, Liu, J, Liu, Q, Tilotson, M, Guan, D and Hubacek, K (2015). Physical and virtual water transfers for regional water stress alleviation in China. Proc. Natl. Acad. Sci., 112(4):

22. Virtual Water Transfer Within China
Much greater amounts than the physical transfers Keep these maps in mind when we look at water footprints
From Zhao, X, Liu, J, Liu, Q, Tilotson, M, Guan, D and Hubacek, K (2015). Physical and virtual water transfers for regional water stress alleviation in China. Proc. Natl. Acad. Sci., 112(4):
Gm3 = giga cubic meter = 1 billion cubic meters

23. Virtual Water Debate Preparation
Get in groups of 4
Prepare to make a case both in support and against the following statement:
More of the world should rely on
virtual water trade
Come up with arguments for and against (10 min)
Discuss the ramifications of these positions (5 min)
Find out where your group members stand on this issue (5 min)

24. Virtual Water Debate Preparation
At the beginning of the next class,
students on one side of the classroom will argue for the affirmative side of the statement
students on the other side of the room will argue the negative side.
Only then will you learn which side of the debate you are on.